Archaeologists working on India's south-west coast believe they may have solved the mystery of the location of a major port which was key to trade between India and the Roman Empire - Muziris, in the modern-day state of Kerala.

For many years, people have been in search of the almost mythical port, known as Vanchi to locals.

Much-recorded in Roman times, Muziris was a major centre for trade between Rome and southern India - but appeared to have simply disappeared.

Now, however, an investigation by two archaeologists - KP Shajan and V Selvakumar - has placed the ancient port as having existed where the small town of Pattanam now stands, on India's south-west Malabar coast.

"It is the first time these remains have been found on this coast," Dr Sharjan told BBC World Service's Discovery programme.

"We believe it could be Muziris."

Key evidence

Pattanam is the only site in the region to produce architectural features and material contemporary to the period.

"No other site in India has yielded this much archaeological evidence," said Dr Roberta Tomber, of the British Museum.

"We knew it was very important, and we knew if we could find it, there should be Roman and other Western artefacts there - but we hadn't been able to locate it on the ground."

Muziris is located on a river, distant from Tindis - by river and sea, 500 stadia; and by river from the shore, 20 stadia

Roman description of the location of Muziris

Until recently, the best guesses for the location of Muziris centred on the mouth of the Periyar river, at a place called Kodungallor - but now the evidence suggests a smaller town nearby, Pattanam, is the real location.

Drs Shajan and Selvakumar now meet locals on a regular basis as they continue their work, with some older people in particular remembering picking up glass beads and pottery after heavy rains.

Undoubtedly, they told Discovery, the many pieces of amphora are from the Mediterranean - a key to establishing Pattanam as the place where Muziris once stood.

"These amphora are so common," Dr Shajan said.

"We have hundreds of shards of Mediterranean pottery."

Mystery disappearance

Muziris became important because of the Romans' interest in trading, and their desire to have contact with regions beyond the reach of conquest and set up trading routes with these places.

"India had a long fascination for the Romans, going back to Alexander the Great," Dr Tomber said.

Glass and precious stones are key finds in the site area

"Alexander was a huge model for succeeding Roman emperors, and the fact that he had been in India and brought back tales of the fantastic things, the people and products there, heightened the Roman desire to continue that association."

What is known, from a 1st Century document, is that the harbour was "exceptionally important for trade."

Clues to its location are provided in ancient Indian texts. Professor Rajan Gerta, from Mahatma Gandhi University in Kerala, said that there are many references to "ships coming with gold, and going back with 'black gold'" - pepper.

"These ships went back with a whole lot of pepper and various aromatic spices, collected from the forests," he added.

Merchants from a number of different cultures are believed to have operated in the port, and there are numerous Indian finds from the time as well as Roman ones.

In 1983, a large hoard of Roman coins was found at a site around six miles from Pattanam.

However, even if Muziris has been found, one mystery remains - how it disappeared so completely in the first place.

Dr Tomber said that it has always been presumed that the flow of the trade between Rome and India lasted between the 1st Century BC through to the end of the 1st Century AD, but that there is growing evidence that this trade continued much longer, into the 6th and early 7th Century - although not necessarily continually.

"We're not quite clear how long it went on in Muziris, and the more evidence we can gather from the artefacts, the clearer the picture that will build up," she added.

"What is interesting is that in the 6th Century, a Greek writer, writing about the Indian Ocean, wrote that the Malabar coast was still a thriving centre for the export of pepper - but he doesn't mention Muziris."